VIRGO (Aug. 23-Sept. 22): Since 1948, the chemical warfarin has been used as a pesticide to poison rats. Starting in 1954, it was prescribed to treat thrombosis and other blood ailments in humans. What is there like warfarin in your life? A person, asset or activity that can be destructive or constructive, depending on the situation? Time will soon be right to use that metaphorical version of warfarin both ways. Make sure you're clear which is which.